Manufacture of alcohols



5 been used to manufacture ethyl alcohol by selec- H MANUr AorUaE oF-AwonoLs g :Yladimir Ipatieff andVasili Komarewsky, c

assignors to'Univcrsal Oil Product s.

' aflompany-gfChicago, 111., a corporation of DeIa-" st' na iie appuaam September 1, 19:3, s SerialNo. 687,843

Claims. (0]. 260-156 This -invention 'relates to the manufacture of alcohols from oleii'ns, particularly oleflns of a normallyv gaseous character such as are encountered in gases from hydrocarbon cracking -5. operations. Y

'In a more specific sense the invention has reference to a process for-the manufacture of relatively low boilingal'cohols using a particular class of acid catalytic reagents. v

The gasesfrom hydrocarbon cracking operations are characterized by a considerable content oi oleflns and-these olefins constitute a primary source. .of reactive hydrocarbon materials, al- I though this reactivity has been made usev of commer'ially'only to a limited extent. Ethylene has tive sulfonation' and hydrolysis and similarly H considerable quantities of isopropyl alcohol have 3 been manufactured. In these processes theusual method ofoperation is to pass the mixture of gaseous hydrocarbons through a stationary body of sulfuric acid of regulated strength (or countercurrent to descending streams of acid in treatingtowers) until a sludge containing acid esters 25 is produced, after which alcohols are obtained bydistilling the sludge after dilution with water, or bydistilling the sludge with steam. In processes using sulfuric acid to produce alcohols from ,olefins difllculties are encountered so owing to the tendency of the sulfuric acid to oxidize and polymerize unsaturated hydrocar-' bons as wellas to form the'desired esters from which the alcohols are obtained by hydrolysis.

Thus, in the case of various butylenes the forma- 35 tion of polymers may exceed the formation of the desiredacidestersand limit the yield of alcohol obtainable. By using the particular acid catalyst reagents and the method of operation comprised within the scope of the present invention many of the undesirable side reactions are eliminated and the yield of alcohols is increased.

In one specific embodiment the invention comprises the treatment of olefinic gases or oleflnic gas mixtures to obtain alcohols therefrom with w 45 phosphoric acid containing metallic salts and/or oxides at pressures up to "atmospheres and temperatures up to 120 C. 7 According to the present process various metal compounds are used to, promote the action of 50 phosphoric acid in producing alcohols from'olefins. Among the metals whose salts and oxides may be used may be mentioned zinc, manganese, molybdenum, iron, nickel, cobalt, etcetera. As a rule these metallic promoters are only used in quantities of 10% and less by weight of the acid 5 and frequently sufllcient promoting action is obtained when using amounts of the order of 5%. Various types of salts may be dissolved in or .mixed with the acid catalyzer, such as nitrates.

chlorides, etcetera and, in the case of some in metals, goodv results are obtained when oxides are dissolved. Owing to the strongly acid character of phosphoric acid some of the salts added will be decomposed so that the weaker acid is displaced and the [resultant fluid mixture contains the phosphate of the metal in solution. How- 'ever, the extent of this action will depend not only upon the irelatire strength of the acid radicals but upon'the co ne'antration of the phosphoric acid, the I temperament-treatment, the amount of metal etc; so that it' is not intended to metalphosphatesresult. i

It will be-seen from the above-brief. enumeration of the .various types of fimetal compounds which may be used as promoters thatfa cons'iderable number of alternatives of varying composition comprising phosphoric acid and metal compounds are possible. However, each catalyst mixture will exert its own specific action in any select reagents from the present group which will produce satisfactory transformation of the olefins into good yields of alcohols.

It is preferable in mostcases to employ the ordinary commercial ortho-phosphoric acid 4 (HaPOO rather than any of the other acids of phosphorus although the invention is not limited to the use of the ortho acid.. In general also the acid of approximately, 90% concentration pro v course of the main reactions leading to the production of alcohols by the present process:

(1) CaHs plus =CaH'IH2PO4 Propylene Phosphoric acid lsdpropyl phosphate (2) C3H7H2PO4 plus H2O==C3H7OH plus HaP04 Isopropyl alcohol The exact mechanism 'of the action of the different'promoters is difllcult to follow and, therefore, it is only possible to suggest what their action is. It may be that there is some intermediate formation of metal salt addition compounds from which the alcohols later result,'or it may be that the action of the metal salt promoters is more definitely catalytic and that such addition compounds if formed are very transient in character and notcapable of separation and identification.

The details of process operation may be varied considerably and both batch and continuous types may be employed. In batch operation phospheric acid and a small amount of a selectedv metal compound promoter may be added to a pressure vessel lined with some corrosion-resistant material and a pure olefin or an olefin-containing gas may be pumped into the bomb until a certain pressure is reached, after which the bomb is heated and the contents agitated either by rotating the bomb or by mechanical stirring-devices. The process is interrupted when the rate of absorption becomes too low as indicated'by a stationary pressure and the liquid products comprising al- .cohols and some polymerized olefins are removed,

after which the cycle is repeated using the same catalyst mixture until its efilciency is lost due to the gradual accumulation of heavy polymers and high molecular weight acid esters. It is characteristic of the present invention that the deterioration of the catalyst is much slower than that of other acid catalysts, particularly sulfuric acid. so that larger yields of alcohols are obtainable for a given amount of catalyst.

In continuous operations an acid catalyst mixture, water or steam and gaseous olefins may be injected simultaneously in regulated proportions into tubular heaters through whichthe reacting components pass and from which they are discharged into a separator or a flash distilling unit. The acid catalyst is then withdrawn frjom the bottom of the distilling chamber-and returned to the entrance of the heating. element for further usewhile the vaporousproducts of the reaction; both hydrocarbons and alcohols, are passed through a fractionating column to obtain desired cuts containing different alcohols in case a mixture of olefins was used. The alcohols in the distillate fractions may be purified and separated from hydrocarbon material by solution in water and a secondary distillation of the aqueous extract.

The following examples are characteristic of results obtainable by the use of the process and are introduced as illustrations but it is to be understood that many others are available.

Example. 1

52 parts by weight of commercial 90%orthophosphoricacid and 5 parts by weight of black nickel oxide were added to a'pressure vessel. 50 parts by weight of propylene were added under a pressure of 120 pounds per square inch after which the temperature was raised to 120 C. and held there until constant pressure conditions obtained.

There was produced by this operation 25 parts by weight of liquid products comprising 60% isopropyl alcohol and 40% propylene polymers, principally dimers and trimers, which were of a character suitable for use as high anti-knock blending fluid in. gasoline.

Example 2 50 parts by weight of 90% orthophosphoric acid and 5 parts by weight of commercial zinc chloride were added to a pressure treater. 50

parts by weight of propylene was added under a pressure of 8 atmospheres and the temperature again raised to 120 C. and maintained at that point until constant conditions were observed.

In this case 22 parts by weight of liquid products were obtained, 62% of which consisted of isopropyl alcohol extractable by water and 38 parts of propylene polymers which as before were utilizable as high anti-knock blending constituents for admixture with gasoline.

The foregoing specification and examples, while disclosing the character of the invention and giving selected results showing its practical value,

are not to be considered as imposing undue limdrocarbons,. the step which comprises treating I the olefin with phosphoric acid in the presence of nickel oxide.

VLADHHIR IPATIEFF.

VASILI ROW. 

